The Square Circle is a 1982 novel by Daniel Carney. It was adapted as the 1985 film Wild Geese II.[1]
After the success of his novel, The Wild Geese (1977) (originally titled The Thin White Line), Carney was asked by producer Euan Lloyd to write a follow-up. Lloyd had already turned The Thin White Line into the hit movie The Wild Geese, and was constantly being asked to make a sequel. At first Carney refused as he just couldn't come up with a premise for the story, Lloyd wouldn't be put off and suggested the theme could be the rescue of Rudolf Hess from Spandau Prison in West Berlin.